Preparation of lipids from plant and animal tissues: Pure compounds and reference mixtures

Summary The systematic analysis of complex lipid mixtures is based on the consecutive application of complementary principles of chromatography. Pure compounds, synthetic standard mixtures, and biological lipid extracts are required as reference materials. Procedures for the preparation of individual compounds and standard mixtures are outlined, and recommendations are offered regarding the choice of biological reference materials and their certification.

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Gewinnung von Lipiden aus pflanzlichen und tierischen Geweben: reine Verbindungen und Referenzgemische

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In this article, lipids have been named according to the Recommendations of the IUPAC-IUB Commission on Biochemical Nomenclature (see Eur J Biochem (1977) 79:11–21)     

Long-term stability of the elemental composition in biological materials

Summary Lyophilized and radiation sterilized biological certified reference materials (CRMs) are believed to be stable in their chemical composition. Generally, the certifying agencies consider the certificates of these biological CRMs valid for a 5-year shelf life, i.e., apart from measurable moisture content, the chemical composition should not change during that time. The long-term behavior of fresh frozen material is not known. In this study the elemental compositions of the Bovine Liver Standard Reference Material (SRM 1577) and human liver tissue samples are evaluated over a time period of more than 7 years. The concentrations of selected elements were determined by neutron activation analysis at various times. The initial evaluation of zinc, selenium and arsenic results gives no indication of changes during 7 years storage of fresh frozen tissues, however, a trend towards lower arsenic concentrations has been observed in SRM 1577 during a 10-year period.

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Langzeitstabilität der Elementzusammensetzung in biologischen Materialien

     

Part IV. Review and evaluation of spark source mass spectrometry as an analytical method

Summary The analytical features and most important fields of application of spark source mass spectrometry are described with respect to the trace analysis of highpurity materials and the multielement analysis of technical alloys, geochemical and cosmochemical, biological and radioactive materials, as well as in environmental analysis. Comparisons are made to other analytical methods. The distribution of the method as well as opportunities for contract analysis are indicated and developmental tendencies discussed.

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Überblick und Bewertung der Funken-Massenspektrometrie als Analysenmethode

Zusammenfassung Die Analyseneigenschaften und wichtigsten Einsatzgebiete der Funken-Massenspektrometrie zur Spurenanalyse an hochreinen Materialien und zur Multielementanalyse an technischen Legierungen, geo- und kosmochemischen, biologischen und radioaktiven Materialien sowie in der Umweltanalytik werden beschrieben. Vergleiche zu anderen Analysenverfahren werden gegeben. Die Verbreitung der Methode sowie Möglichkeiten der Auftragsanalytik werden angegeben und Entwicklungstendenzen diskutiert.

     

Multipurpose biological reference materials

Summary Reference materials to meet multipurpose needs for analysis of both inorganic and organic constituents in biological investigations are not readily available. A human total diet material is being investigated as a reference material for a wide variety of constituents of interest to human nutrition and health. This material shows a stable assay value for the natural levels of a number of vitamins following freeze-drying or radiation sterilization. This is an important feature in producing materials for long term stability as a Reference Material for natural levels of these constituents. An exception is an increase of 34% in assay value of folic acid upon freeze-drying and an 85% increase upon freezedrying followed by radiation sterilization.

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Vielseitig verwendbare biologische Referenzmaterialien

     

BCR edible oils and fats reference materials

Summary The Community Bureau of Reference (BCR) has recently made available three certified reference materials (CRM's) viz. a soya-bean oil/maize germ oil blend, a beef fat/pig fat blend, and an anhydrous milk fat (butterfat) with added vanillin and phytosterols. The results from inter-laboratory studies designed to obtain certified and indicative values for specific properties of the materials are reviewed and the application of the CRM's in quality assurance and method validation/standardisation described.

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BCR-Referenzmaterialien für Speiseöle und -fette

     

Quantitative spektrochemische Untersuchungen mit Lichtbogenanregung an biologischen Analysenmaterialien

Zusammenfassung Bei der spektroskopischen Analyse wasserhaltiger biologischer Substanzen treten erhebliche Fehlerquellen auf. Bei dem angegebenen Verfahren wird die Analysenlösung auf einem Filterpapierstreifen eingetrocknet und dann im Gleichstrombogen angeregt; das Bezugselement kann gesondert aufgebracht werden. Fehler- und Nachweisgrenzen werden angegeben.

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Summary There are many error sources in spectroscopic analysis of aqueous biological materials. To avoid at least some of them, in the method reported the analysis solution is dryed on a stripe of filter paper, and burnt and excited in a d.c. arc. The reference element can be added to the stripe seperately from the analysis material. Limits of error and detection are indicated.

     

NBS activities in biological reference materials

Summary NBS activities in biological reference materials during 1986–1988 are described with a preview of plans for future certifications of reference materials. During the period, work has been completed or partially completed on about 40 reference materials of importance to health, nutrition, and environmental quality. Some of the reference materials that have been completed during the period and are described include: creatinine (SRM 914a), bovine serum albumin (SRM 927a), cholesterol in human serum (SRM's 1951–1952), aspartate aminotransferase (RM 8430), cholesterol and fat-soluble vitamins in coconut oil (SRM 1563), wheat flour (SRM 1567a), rice flour (SRM 1568a), mixed diet (RM 8431a), dinitropyrene isomers and 1-nitropyrene (SRM 1596), and complex PAH's from coal tar (SRM 1597). Oyster tissue (SRM 1566a) is being analyzed and should be available in 1988.

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NBS-Aktivitäten in biologischen Referenzmaterialien

     

Criteria for the development of biological reference materials

Summary A review is presented of factors to be considered in the development of biological reference materials. Some guidelines are offered regarding approaches to the generation of the varied materials required for analytical quality control. Major considerations in such an endeavour are the goal of the undertaking and role of the final product, selection of candidate materials, preparation, characterization and certification. Selection of materials should be from those important to commerce and consumers, and related to various regulatory, clinical, environmental, and research activities. They should adequately represent the different choices and types of foodstuffs, clinical materials and environmental materials, such as soils, sewage sludges, plant and animal tissues, of interest in different regions of the world.Acquisition can be from commercial sources or the result of in-house preparation, with attention to stability enhancement if required and maintenance of native analyte levels by minimization of contamination. The approach to chemical and physical characterization relies on the measurement philosophy, selection of analytes, their speciation, and selection of analytical methods and analysts for establishment of homogeneity and quantitative levels. Throughout the overall task of RM development there is a requirement for a critical approach by critical analytical and measurement scientists and the involvement of national RM agencies in order to produce top quality control materials.

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Kriterien für die Entwicklung von biologischen Referenzmaterialien

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Contribution No. 88-50 from Land Resource Research Centre     

Rapeseed reference materials for glucosinolate analysis

Summary The use of rapeseed cake is limited by the presence of a number of antinutritional factors the most important of which are glucosinolates. Introduction by EEC of a premium to produce rapeseed with low glucosinolate content has brought the need for reference material and accurate official methods of analysis. This paper summarises the work, begun at the end of 1987, to prepare three batches rapeseed materials (cleaning, mixing and packaging) for an intercomparison of methods. Details are presented of homogeneity and stability studies and the results of the intercomparison are discussed. One of the batches was prepared in sufficient quantity to serve as a reference material and the reference value for the total glucosinolate content of this sample was obtained from the results of the intercomparison.

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Rapssamen-Referenzmaterial für die GlucosinolatanalyseEntwicklung von Rapeseed BCR RM 190 und Ergebnisse eines Ringversuchs

     

Preparation of twelve candidate agricultural reference materials

Summary A cost-effective approach to monitoring and maintaining reliability of analytical procedures is by the incorporation of appropriate, compositionally similar reference materials into the scheme of analysis. Agricultural and food commodities represent an extremely wide range of composition, in respect of the sought-for analyte and the supporting material (matrix), not fully reflected in currently available biological reference materials (BRM's). With the view to attempting to fill some of the gaps in the world repertoire of reference materials and to have suitable products for our laboratories' use, preparation has been completed of twelve candidate agricultural reference materials. These products, representing a number of food classes, include bovine muscle powder, hard red spring wheat flour, soft winter wheat flour, durum wheat flour, wheat gluten, corn bran, corn starch, potato starch, whole egg powder, whole milk powder, microcrystalline cellulose, and sugar. Preparative steps included, as required, freeze drying, grinding or ball milling, X-ray sterilization, sieving, blending and packaging to yield sizeable quantities of each material in finely powdered form. Cooperative analytical effort is expected to lead to characterization in respect of concentrations of a number of nutritionally, toxicologically and environmentally-pertinent, major, minor, and trace chemical elements. These materials will then be available for analytical chemical data quality control for inorganic constituents in a range of agricultural commodities.

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Herstellung von zwölf als landwirtschaftliche Referenzmaterialien vorgeschlagenen Substanzen

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Contribution No. 88-49 from Land Resource Research Centre     

Erste Ergebnisse einer Ringanalyse zur Erstellung eines internen Buchenblatt-Referenzmaterials für ?kosystemuntersuchungen

Summary To evaluate pollution effects on ecosystems, more and more plant and animal samples are analyzed for their concentrations of pollutants and nutrient elements. Since chemical analyses of biological materials are largely influenced by matrix effects, their accuracy depends on the availability of reference materials. Unfortunately only very few such standards exist so far. The described interlaboratory comparison of beech leaves from Baden-Württemberg demonstrates the possibility of producing reference materials from selected organisms, which — though not certified — are sufficient for research projects. Apart from their function as reference materials, those standards show typical levels of elemental concentrations for their region of origin. First results are introduced.     

A new analytical system for multicomponent gas-chromatographic analysis of metabolites in biological material

Summary A new method for the gas-chromatographic multicomponent analysis of metabolites in biological material is described. It is an analytical procedure involving several extractions carried out under different conditions. In this procedure the metabolites are divided according to their functional groups and specific chemical behaviours into eight main fractions: lipids, hydrocarbons, organic acids, neutral substances, phenols, amines, amino acids and carbohydrates. Each of these fractions is derivatized; the components are separated and estimated by gas chromatography. This analytical system was applied to the determination of a number of metabolites in serum, urine, amniotic fluid, sperma, tissues and other biological materials.

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Neues Analysensystem zur Multikomponenten-GC-Analyse von Metaboliten in biologischem Material

Zusammenfassung Eine Methode für die Multikomponenten-GC-Analyse von Metaboliten in Biomaterialien wird beschrieben. Das Verfahren umfaßt mehrere Extraktionen, die unter verschiedenen Bedingungen durchgeführt werden. Die Komponenten werden in Abhängigkeit von ihren funktionellen Gruppen und spezifischem chemischen Verhalten in acht Hauptfraktionen geteilt: Lipide, Kohlenwasserstoffe, organische Säuren, neutrale Substanzen, Phenole, Amine, Aminosäuren und Kohlenhydrate. Die Komponenten jeder Gruppe werden nach spezieller Derivatisierung gaschromatographisch getrennt und bestimmt. Dieses neue System ist bei verschiedenen biologischen Materialien (klinische Proben, Pflanzen- und Tiergewebe) angewandt worden.

     

NAA methods for determination of nanogram amounts of arsenic in biological samples

Summary The determination of arsenic at natural levels in biological materials remains difficult. Many analytical techniques cannot detect the low levels present in typical biological tissues and other techniques suffer from interferences. This paper reviews uses of neutron activation analysis (NAA) at NIST to determine nanogram amounts of arsenic in biological reference materials with radiochemical (RNAA) or instrumental (INAA) procedures. INAA is compromised by high activities from ²⁴Na, ⁸²Br, and ³²P that may be formed during irradiation of biological tissues, and result in detection limits as high as 0.1 mg. Lower detection limits have been achieved using state-of-the-art gamma-ray spectrometry systems in INAA and a variety of procedures in RNAA. These techniques and procedures were applied recently at NIST to the determination of arsenic in urine, nutritional supplements, and total diet samples.     

Vanadium biomonitoring by using <Emphasis Type="Italic">Perna perna</Emphasis> (Linnaeus, 1758) mussels transplanted in the coast of the State of São Paulo,Brazil

The increased pollution in the aquatic ecosystem has led to the investigation of toxic elements in sea water by using marine organisms to assess marine pollution from human activities. Among these organisms, the mollusks bivalves have been used as biomonitors since they can accumulate trace elements and other substances, without the occurrence of their death. In this study, Perna perna mussels were transplanted from a mussel farm (reference region) to four sites located in coastal regions of São Paulo State, Brazil, close to anthropic discharge areas. Vanadium was determined in mussel tissues by instrumental neutron activation analysis (INAA). Quality control of V analysis was checked by analyzing biological reference materials and the results obtained were precise and in good agreement with the certified values. Comparisons between the V concentrations obtained in transplanted mussels indicated that those from São Sebastião region, close to an oil terminal presented the highest concentration of this element, during spring.     

The use of reference materials in the finnish industry

Summary A report is given on the results of a survey of the use of reference materials in the chemical industry of Finland. It has been found that there is virtually no production of reference materials in Finland and that most of the materials used are not certified. Mostly, different materials are used which are pharmacopoeia standards with regard to their physical properties. Some companies were found to use more than 100 different reference materials.

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Verwendung von Referenzmaterialien in Finnland

Zusammenfassung Es wird über das Ergebnis einer Umfrage zur Benutzung von Referenzmaterialien in der chemischen Industrie Finnlands berichtet. Es ergab sich, daß in Finnland praktisch keine solchen Substanzen hergestellt werden und die meisten der verwendeten Materialien nicht zertifiziert sind. Meist werden verschiedenartige chemische Substanzen verwendet, die in Bezug auf ihre physikalischen Eigenschaften einem Arzneibuchstandard entsprechen. Einige Firmen benutzen mehr als 100 verschiedene Referenzmaterialien.

Presented at Euroanalysis III conference, Dublin, August 20–25, 1978     

Matrix effects and analysis of biological material by spark source mass spectrometry

Summary Spark-source mass spectrometric analyses of synthetic simulated biological samples were performed to determine the importance of matrix effects. A correlation between the variation of the relative sensitivity coefficients (RSC's) and the spark plasma composition, hence plasma temperature, was found. The determined RSC's were used in the analysis of four biological standard reference materials. An accuracy of 10–13% and detection limits between 0.005 and 0.5 ppm were obtained during analysis under normal conditions.

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Matrixeffekte und Analyse von biologischem Material mit Hilfe der Funkenionen-Massenspektrometrie

Zusammenfassung Um die Bedeutung von Matrixeffekten zu untersuchen, wurden Analysen von synthetischem biologischem Material mit der Funkenquellen-Massenspektrometrie durchgeführt. Dabei wurde eine Beziehung zwischen der Veränderung der relativen Empfindlichkeitskoeffizienten und der Zusammensetzung des Funkenplasmas (und damit der Plasmatemperatur) festgestellt. Die bestimmten Empfindlichkeitskoeffizienten wurden zur Analyse von vier biologischen Standardreferenzmaterialien eingesetzt. Unter normalen Bedingungen wurde eine Genauigkeit von 10–13% und Nachweisgrenzen zwischen 0,005 und 0,5 ppm erreicht.

     

Literature survey on thermal analysis reference materials

Results of a literature search on thermal analysis reference materials are listed

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Zusammenfassung Vorliegend werden die Ergebnisse einer Literaturrecherche über Referenz-substanzen für die thermische Analyse dargelegt.

     

New developments in trace element analysis in the life sciences

Summary In the analysis of trace elements in biological materials it has become more and more apparent that there is often a need not only to determine the levels of the elements in the whole sample but also to measure the element contents in fractions of the materials, such as certain types of cells, subcellular components and molecules. Furthermore, it is sometimes necessary to relate the elemental data to relevant biological and biochemical parameters as there is otherwise a danger that wrong conclusions may be drawn. In this paper these trends in trace element analysis are described with the help of examples and the problems which can occur in the various steps of sampling and sample preparation are discussed.

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Neue Entwicklungen bei der Spurenelementanalyse in den Biowissenschaften

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Dedicated to Prof. Dr. G. Tölg on the occasion of his 60th birthday     

Improvements in the analysis of chlorobiphenyls prior to the certification of seven CBs in two fish oils

Summary This paper gives an account of the systematic, collaborative learning programme undertaken by a group of experienced analytical laboratories within the European Economic Community (EEC) to improve the state-of-the art in the determination of individual chlorobiphenyl congeners in different matrices in preparation for the certification exercises to produce two fish oils as certified reference materials (CRMs). The choice of individual CB congeners, the critical GC parameters necessary to optimise the chromatographic separation and quantification of the congener is given. An assessment is made of the methods of extraction, separation and clean-up of samples prior to gas chromatographic analysis.

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Verbesserung der Analyse von Chlorbiphenylen vor der Zertifizierung von sieben CBs in zwei Fischölen